The object of this study is the copper slag from the Kirovgrad (originally Kalatinsky) plant, operating since 1914, around which the modern city of Kirovgrad (Sverdlovsk region, Middle Urals) has gradually grown. The material composition of the studied samples is obtained by scanning electron microscopy and inductively coupled plasma mass spectrometry. It has been established that they are represented by two types with distinct mineralogical and geochemical characteristics. The first type is composed of a fayalite-augite aggregate containing magnetite, chromite, and arsenide-stibnide-sulfide mineralization, as well as copper and silver. Chalcogenides are represented by troilite, cubanite, haycockite, rudashevskite, galena, breithauptite, westerveldite, and Cu-Fe sulfides. The second type is a fayalite-hedenbergite aggregate with significant amounts of magnetite, glass, and arsenide-stibnide-sulfide mineralization, as well as barkovite, copper, and silver. Chalcogenides are represented by bornite, chalcocite, sphalerite, galena, pentlandite, heazlewoodite, breithauptite, nickeline, and shandite. The slag mineralogy is consistent with their trace element composition. It is concluded that the first type of slag resulted from the smelting of copper pyrite ores from the Levikhinsky group of deposits, while the second type resulted from the smelting of polymetallic ores from the Safyanovsky deposit. Slags from the Kirovgrad plant can be processed to extract sulphide and magnetite concentrates, and associated silver.